I really don't agree with anything you say here and what else would low level mean?
You are free to disagree with the assessment, but it doesn't change the fact what you are talking about is pretty much the definition of racism:
http://www.merriam-webster.com/dictionary/racism
https://en.wikipedia.org/wiki/Racism
"The ideology underlying racist practices often includes the idea that humans can be subdivided into distinct groups that are different in their social behavior and innate capacities and that can be ranked as inferior or superior."
You are effectively bundling a certain group of people (immigrants with low levels of education), and you are assuming that other immigrants with low levels of education do the same, and adding to this, you seem to be suggesting that "natives" with a low level of education would do a better job, because if they didn't what would be the point of not having immigrants?
As for what else low level could mean, maybe I am mistaken since I'm not a native speaker, but I believe low level could be used to describe someone that is inferior to someone else in a myriad of ways, and not merely education.